AC Susceptibility and Superconducting Properties of Graphene Added YBa2Cu3O7−d

Abstract

The effect of graphene (G) addition on YBa2Cu3O7−δ(G)x (x = 0 − 0.03 wt%) has been studied using the X-ray diffraction method, scanning electron microscopy, electrical resistance versus temperature, transport critical current density Jc, and AC susceptibility measurements. XRD patterns showed single-phase YBa2Cu3O7−δ (YBCO) for all samples. SEM micrographs showed filling of the voids between YBa2Cu3O7−δ grains as graphene was added. The temperature-dependent electrical resistance curves showed metallic normal state behavior and onset transition temperature Tconset between 90 and 92 K for all samples. AC susceptibility measurement showed transition temperature $T_{\mathrm {c} \chi ^{\prime }}$ between 90 and 93 K. $T_{\mathrm {c} \chi ^{\prime }}$ was maintained or improved slightly as graphene was added. The x = 0.001 wt% showed the highest Jc, i.e., 2750 A cm−2 at 77 K and 5570 mA cm−2 at 30 K which was 13 and 40 times higher than that of the non-added YBCO, respectively. The peak temperature Tp of the imaginary part of the susceptibility χ″ was around 78–82 K for all samples indicating grain coupling was not weakened as graphene was added.